From 8d4bd0ed0439dfc780aab801a085961925ed6838 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Tue, 8 Sep 2015 15:25:39 +0200 Subject: [PATCH] s390/compat: correct uc_sigmask of the compat signal frame The uc_sigmask in the ucontext structure is an array of words to keep the 64 signal bits (or 1024 if you ask glibc but the kernel sigset_t only has 64 bits). For 64 bit the sigset_t contains a single 8 byte word, but for 31 bit there are two 4 byte words. The compat signal handler code uses a simple copy of the 64 bit sigset_t to the 31 bit compat_sigset_t. As s390 is a big-endian architecture this is incorrect, the two words in the 31 bit sigset_t array need to be swapped. Cc: Reported-by: Stefan Liebler Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/compat_signal.c | 27 +++++++++++++++++++++++---- 1 file changed, 23 insertions(+), 4 deletions(-) diff --git a/arch/s390/kernel/compat_signal.c b/arch/s390/kernel/compat_signal.c index eb4664238613..e0f9d270b30f 100644 --- a/arch/s390/kernel/compat_signal.c +++ b/arch/s390/kernel/compat_signal.c @@ -48,6 +48,19 @@ typedef struct struct ucontext32 uc; } rt_sigframe32; +static inline void sigset_to_sigset32(unsigned long *set64, + compat_sigset_word *set32) +{ + set32[0] = (compat_sigset_word) set64[0]; + set32[1] = (compat_sigset_word)(set64[0] >> 32); +} + +static inline void sigset32_to_sigset(compat_sigset_word *set32, + unsigned long *set64) +{ + set64[0] = (unsigned long) set32[0] | ((unsigned long) set32[1] << 32); +} + int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from) { int err; @@ -281,10 +294,12 @@ COMPAT_SYSCALL_DEFINE0(sigreturn) { struct pt_regs *regs = task_pt_regs(current); sigframe32 __user *frame = (sigframe32 __user *)regs->gprs[15]; + compat_sigset_t cset; sigset_t set; - if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE32)) + if (__copy_from_user(&cset.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE32)) goto badframe; + sigset32_to_sigset(cset.sig, set.sig); set_current_blocked(&set); save_fpu_regs(); if (restore_sigregs32(regs, &frame->sregs)) @@ -302,10 +317,12 @@ COMPAT_SYSCALL_DEFINE0(rt_sigreturn) { struct pt_regs *regs = task_pt_regs(current); rt_sigframe32 __user *frame = (rt_sigframe32 __user *)regs->gprs[15]; + compat_sigset_t cset; sigset_t set; - if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) + if (__copy_from_user(&cset, &frame->uc.uc_sigmask, sizeof(cset))) goto badframe; + sigset32_to_sigset(cset.sig, set.sig); set_current_blocked(&set); if (compat_restore_altstack(&frame->uc.uc_stack)) goto badframe; @@ -377,7 +394,7 @@ static int setup_frame32(struct ksignal *ksig, sigset_t *set, return -EFAULT; /* Create struct sigcontext32 on the signal stack */ - memcpy(&sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE32); + sigset_to_sigset32(set->sig, sc.oldmask); sc.sregs = (__u32)(unsigned long __force) &frame->sregs; if (__copy_to_user(&frame->sc, &sc, sizeof(frame->sc))) return -EFAULT; @@ -438,6 +455,7 @@ static int setup_frame32(struct ksignal *ksig, sigset_t *set, static int setup_rt_frame32(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs) { + compat_sigset_t cset; rt_sigframe32 __user *frame; unsigned long restorer; size_t frame_size; @@ -485,11 +503,12 @@ static int setup_rt_frame32(struct ksignal *ksig, sigset_t *set, store_sigregs(); /* Create ucontext on the signal stack. */ + sigset_to_sigset32(set->sig, cset.sig); if (__put_user(uc_flags, &frame->uc.uc_flags) || __put_user(0, &frame->uc.uc_link) || __compat_save_altstack(&frame->uc.uc_stack, regs->gprs[15]) || save_sigregs32(regs, &frame->uc.uc_mcontext) || - __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)) || + __copy_to_user(&frame->uc.uc_sigmask, &cset, sizeof(cset)) || save_sigregs_ext32(regs, &frame->uc.uc_mcontext_ext)) return -EFAULT; -- 2.11.4.GIT